1. Technical Field
Embodiments of the present disclosure generally relate to semiconductor devices configured for performing a refresh operation and semiconductor systems including the same.
2. Related Art
Dynamic random access memory (DRAM) devices among memory semiconductor devices may lose data stored in their memory cells as time elapses even while their power supplies are applied thereto, in contrast to static random access memory (SRAM) devices or flash memory devices. In order to prevent the data stored in the DRAM cells from being lost, the DRAM devices may be accompanied, basically, with an operation for rewriting the data from external systems in a certain period, which is called “a refresh operation”. Usually, such a refresh operation is carried out, in retention times that are inherent in memory cells of banks, by activating word lines at least once or more, and sensing and amplifying data of the memory cells. The retention time is a time for which data can be maintained without a refresh operation after being written into a memory cell. Generally, DRAM devices accompanied with the refresh operation may perform an internal operation such as a read operation or a write operation.